巨型撞击造成月背深部物质丢失

Core Viewpoint - The research conducted by the Chinese Academy of Sciences reveals that the large impact event approximately 4.25 billion years ago in the South Pole-Aitken Basin not only created the largest crater on the Moon but also caused the loss of certain volatile elements from the Moon's deep material due to high-temperature conditions [1][2]. Group 1: Impact of Large Collision - The South Pole-Aitken Basin is the largest impact basin on the Moon, and the samples collected by the Chang'e 6 mission provide critical insights into the effects of this large impact event [1]. - The study highlights that asteroid impacts have been the primary external force shaping the Moon's surface since its formation, leading to significant changes in its topography and chemical composition [1]. Group 2: Isotope Analysis and Findings - The research team performed high-precision potassium isotope analysis on the basalt samples returned by Chang'e 6, revealing a significantly higher proportion of the heavier potassium isotope (K-41) compared to samples from the Moon's near side [2]. - The study concluded that the early large impact event altered the potassium isotope composition of the Moon's deep mantle, with the high-temperature and high-pressure conditions during the impact causing the lighter potassium isotope (K-39) to escape, resulting in a relative enrichment of K-41 in the remaining material [2]. Group 3: Implications for Lunar Evolution - The loss of volatile elements due to the impact may have further suppressed volcanic activity on the Moon's far side, providing key scientific clues for understanding the impact of large collisions on lunar evolution [2]. - This research helps explain the geological evolution differences between the Moon's near and far sides, offering insights into the Moon's overall geological history [2].